Radio Frequency Identification
Radio frequency identification systems have been frequently used to automatically identify objects. One example of a practical application of this technology has resulted in electronic identification of individual animals. The basic elements of such systems include a reader/transmitter, an antenna and a transponder which is attached to an individual animal. The reader/transmitter sends an electromagnetic wave through the antenna to the transponder, which uses this energy to transmit a radio frequency signal back through the antenna to the reader/transmitter. Typically, the signal includes an identification code unique to each transponder. In order to monitor the activities of large herds or groupings of animals, one must be able to monitor multiple transponders. With currently available technology, it is extremely difficult to read multiple transponders using one reader/transmitter.
If each one of the multiple transponders uses the same frequency to transmit its unique identification code back to the reader/transmitter, a single reader/transmitter is unable to readily decipher each individual identification code. In order to make systems with multiple transponders operational, multiple reader/transmitters are required which, in turn, render such systems costly, and will also reduce the area in which the transponders can be simultaneously read.
Measuring Feed Intake—Previous Generation Feed Intake Measurement
A rudimentary way to measure individual feed or water intake has been to house animals individually and record consumption amounts by measuring and manually recording the feed supplied minus the feed refused or remaining. This method is both labor intensive and cost prohibitive. Studies of both swine and cattle have demonstrated that individually housed animals alter their performance significantly from those fed in production environments.
The first generation of electronic feeders acted on the same principle as manual recording. These systems isolate one animal to an individual feeding gate or stall. When the animal enters the stall, the starting trough weight is recorded and, when the animal leaves, the end trough weight is recorded. The difference between starting weight and end weight is determined to be equal the feed intake. Although a gross measurement of what feed disappeared during the time the animal entered and left the feeding stall, this measurement does not take into account what precisely happened during the time period.
The methodology is further compromised when the access to the trough is open at all times and RFID is utilized to identify the animal. RFID is position sensitive and, therefore, might require a variable amount of time to read, compromising the start of the event. Other issues complicating the use of RFID, particularly when measuring visitation by an individual animal to a trough is that the RFID reading field often extends to one or more adjacent trough areas. It is therefore possible when the animal has its head close to one side or the other of a feeding trough that the adjacent RFID antenna also reads the adjacent animal's RFID tag and this potentially creates reading/calculation problems.
These first generation systems typically must be housed in barns providing protection from wind and other environmental conditions adding significantly to the cost of measurement. On a windy day for example, the wind or air pressure applied to the trough often varies by 10N. Such pressure variation becomes very problematic when trying to weigh a typical feed intake meal event normally about 800 grams.
It is to be appreciated that little to no behavioral information is acquired by these first generation systems. Inter-meal activity is not recorded. The effect of animal competition, on intake feeding behavior, is not adequately measured and feeding rates are normally considered to be constant during a feeding event. In terms of behavioral measurement, perhaps the most limiting factor is that the equipment determines what a feeding event or meal event is, by virtue of an animal visit being recorded by the equipment.
An other issue, arising from the use of such equipment, is that typical feeding behaviors are severely modified by the design of the measurement device itself. The animal may only be allowed to visit its specific feed stall to record consumption. Or when two animals wish to enter the trough at the same time, none of the animals will gain access. To overcome the limitations of the system to read multiple tags in close proximity, the system prevents access to feed.
Several of these early generation systems did not include a method to account for feed appearing in the trough. Some tried to properly account for feed appearing by using deflectors that kept animals from the bunks when troughs were being filled. Animals were refused entrance when feed resupplying occurred.
The first generation systems did not include the ability to audit or assess the accuracy of measurements. Several researchers have developed generalized and average statistical assumptions to overcome errors occurring in the first generation systems. In scientific literature, incorrect data is usually adjusted per visit. (e.g., De Haer et al., 1992). Some studies correct for measurement error by estimating individual feed intake of animals and tolerance factors based on those taken in group feeding studies. This circular reasoning does not improve measurement accuracy though data may fit what the researcher perceives to be true based on prior research in group settings.
Background to Feeding Behavior Measurement
In the early 1990s GrowSafe Systems Ltd, (“GrowSafe”) developed a computerized data acquisition system that could electronically identify and monitor ostrich chicks. Chicks would visit the feeder about 500 times per day. When chicks became ill, feeding behavior visitation dropped rapidly, declining to about 50 visits per day. This decline in visitations could be trended over a very short time interval, usually within about 4-12 hours. In response to GrowSafe data triggers, avian specialists developed responsive treatment protocols. Using the GrowSafe technology and responsive animal health treatment protocols incorporated therein, the survival rate of the subjects tested improved from 8% to more than 90% (Huisma anecdotal 1993).
Early findings in cattle research, using GrowSafe technology, indicated similar early predictive abilities using animal behavior to identify illnesses at an earlier point in time than otherwise possible. From 1993 to 2000 a significant body of work was compiled by researchers using first generation GrowSafe behavior research technology indicating that feeding behavior patterns, of morbid and non-morbid calves, differ and could be measured (Basarab, 1996); and that the technology had the potential to identify morbid animals before any overt disease symptoms could be detected (Quimby 1999). Research determined that the economic value of morbid calves could be as much as US$0.19 to $0.35 less per kg than for healthy calves (Sowell 1999).
The technological transition from a GrowSafe system that could measure a small bird confined in a controlled environment to a large animal in the cattle environment was extremely complex and required the adaptation and development of new electronics, wireless communication methods, and data acquisition and analysis techniques. Many of these methods are currently protected by patents issued or assigned to GrowSafe Systems Ltd.
Feeding Behavior and Sickness Identification
Researchers have traditionally viewed behavioral changes as simple signs of the debilitative effects of disease. (Weary 2009). Results from several key studies now indicate (1) sickness behavior is a motivational state; (2) sickness behavior is a well-organized adaptive response to infection; (3) cytokines produced by activated leukocytes induce sickness behavior; and (4) cytokines transmit messages from the periphery to the brain using humoral and neural pathways (Johnson 2002). Over the past decade, a substantial shift in thinking about behavioral concepts relating to animal health has occurred.
Identifying sick animals, early in the course of the disease, can be one of the toughest jobs in livestock production. When treated early, most animals have an excellent chance at survival but if an animal is sick for even a few days, treatment regimens are less likely to be effective. The recognition in declines of feed intake can assist with the identification of sick animals. In recent years there has been an increased interest in behavioral indicators of disease. A decrease or change in feeding patterns are usually symptoms of sick individuals. Research has demonstrated decreases in the carcass value of sick animals between animals that have not been treated and those that have been treated once, twice and three times respectively (Schneider 2009). The value of rapid diagnosis and treatment of disease increases when cattle are sold on carcass merit basis because of the negative effects of disease on carcass traits (Larson 2005).
Several epidemiological studies have indicated that even with increased pharmaceutical use, the incidence of morbidity and mortality in feedyards has increased. Total feedlot deaths in 2003 increased by 69% when compared to those in 1994. Bovine Respiratory Disease (BRD deaths more than doubled (118%) during same time period (Loneragan 2008).
Research indicates that the timing of initial BRD treatment is associated with performance and health outcomes (Babcock 2009) The effectiveness of antimicrobials in the treatment of BRD depends primarily on early recognition and treatment (Apley 2007 Cusack 2003). BRD manifests its economic losses cumulatively, through the cost of treatment, the cost of lost production, and loss due to death, thus emphasizing the importance of prevention and treatment of BRD as early as possible.
Feed Efficiency
For many years, genetic selection programs have focused on production (output) traits, with little attention given to production costs (inputs). Recently, this view has begun to change, and the efficiency of conversion of feed (i.e., the amount of product per unit of feed input) has been recognized as more important.
Within any beef cattle operation, feed costs are undoubtedly the main concern since they typically account for about 60-65% of the total costs of production. Because of the large costs associated with feed, increasing the efficiency of feed has been targeted as a means of improving the profitability of the beef industry. One estimate of feed efficiency is the feed conversion ratio. Traditionally, this was expressed as a feed:gain ratio, but this led to the confusing result that a higher ratio meant a lower efficiency. Today, to overcome this problem, the feed conversions are often expressed as a gain:feed ratio. Even so, results can be misleading, because these ratios are closely correlated to the intake and rate of gain of the animal (Carstens et al., 2004).
Two animals might have a similar gain:feed ratio and still be very different in their feed intakes and rates of gain. Conversely, the same animal at different intakes would certainly have different gain:feed ratios, even though the genetics of the animal had not changed. Therefore, gain:feed ratios have never been widely recognized as a criterion for genetic selection. Residual feed intake (RFI), defined as actual feed intake minus the expected feed intake of each animal, was first proposed as an alternate measure of feed efficiency by Koch et al. (1963). It can be defined, in other words, as the difference between actual feed intake and the expected feed requirements for maintenance of body weight and for weight gain. In contrast to gain:feed, residual feed intake is independent of growth and maturity patterns. Therefore, RFI should be a more sensitive and precise measurement of feed utilization, since it is based on energy intake and energy requirements.
RFI is an individual animal record, taking into account feeding trials. Accurate measurements of daily feed consumed must be made as well as average daily gain. Research has found that there is considerable variation in individual animal feed intakes, both above and below that which is expected or predicted on the basis of size and growth. These findings, along with the fact that individual animals of the same body weight require rather widely differing amounts of feed for the same level of production establishes the scientific base for measuring RFI in beef cattle. (Sainz et al, 2004).
Manure and GHG Emission Reduction
Relative to high RFI cattle, low RFI cattle have been shown to emit less methane—a potent greenhouse gas (GHG). Scientific evidence indicates that a reduction in methane and manure production can be achieved by with a low RFI that is through the reduction in feed intake (Arthur 2009).
Animal Welfare
Animal welfare is a complex issue that includes important scientific, economic and ethical considerations. This issue has the potential of impacting profitability across the entire meat and dairy chain if the end result of animal welfare initiatives requires the adoption of different farming practices or processing methods.
Early identification of sickness, reduction of farm yard stress, animal behavioral measurement and an ability to monitor the welfare and mitigate adverse conditions, for individual animals, is an important animal welfare and research priority.
Antimicrobial Resistance
Current legislation was introduced in March 2009 in the U.S. House of Representatives to prevent the use of antibiotics, important to human health, from being used non-therapeutically in animals. In North America, a ban on the use of antimicrobials for prophylaxis would result in a further increase in the incidence of clinical disease, decreased performance and increased costs of production. The beef cattle feedlot industry has not explored cost-effective feeding and production alternatives to the use of antimicrobials for disease prevention.
It is likely that in response to animal welfare and consumer demand that pharmaceutical products will be targeted to individuals requiring treatment.